Add AWS Region Comparison Link to Cloud Posse Documentation

[osterman]

To improve the usability of our Decide on Primary AWS Region documentation, add a link to the AWS Region Comparison tool: https://region-comparison.aws.com/.

Update: https://docs.cloudposse.com/layers/network/design-decisions/decide-on-primary-aws-region/

Add a link to https://region-comparison.aws.com/

This tool provides an easy way to compare regions based on services, features, and compliance, helping users make more informed decisions when selecting their primary AWS region.